diff --git a/lib/pact/consumer_contract/query.rb b/lib/pact/consumer_contract/query.rb
index 0a46ec7..af91613 100644
--- a/lib/pact/consumer_contract/query.rb
+++ b/lib/pact/consumer_contract/query.rb
@@ -109,6 +109,18 @@ def self.params_hash_type?(obj)
       obj.is_a?(Hash)
     end
 
+    def self.params_hash_has_key?(hash, key)
+      return false if /\[\]/.match?(key)
+
+      key.split(/[\[\]]+/).inject(hash) do |h, part|
+        next h if part == ''
+        return false unless params_hash_type?(h) && h.key?(part)
+        h[part]
+      end
+
+      true
+    end
+
     def self.unescape(s, encoding = Encoding::UTF_8)
       URI.decode_www_form_component(s, encoding)
     end